Isatin-carbazole compound vat dyestuff



Patented Dec. 22,1939

UNITED STATES PATENT FFlQE MAXIMILIAN PAUL SCHMIDT, OF \VIESBADEN, AND OTTO LIMPACH, OF BIEBRICH,

GERMANY, ASSIGNORS TO GENERAL ANILINE CORPORATION OF DELAWARE WORKS, INC., OF NEW YORK, N. Y., A

ISATIN-CARBAZOLE CQMPGUED VAT DYESTUFF NO Drawing. Application flied July 8, 1929, Serial 150. 376,843, and in Germany July 21, 1928.

'ing from the carbazole-N-substituted hydroXy-benzo-oarbazoles. In this way a much greater fastness of the dyestuffs to chlorine,

to light and to staining is obtained without detriment-ally affecting the good properties inherent in this class of bodies-such as their great a'fiinity for the fiber being thereby diminished especially in so far as they are utilized for printing purposes.

The following example serves to illustrate our invention, but it is not intended to limit thereto; the parts being by weight:

247 parts of N-methyl-L2-(lhydroxybenzo) -carbazole of the formula:

are heated together with 222 parts of isatina-anilid in acetic anhydride until there can no longer be detected in the mixture any anilid. After cooling the dyestuff thus obtained is filtered by suction and Washed with alcohol. There is obtained a bluish-black crystalline powder which probably has the following formula being a bluish-black crystalline powder, yield ing with an aqueous alkali and hydrosulfite a yellow Vat dyeing cotton and wool a yellow tint which turns deep black on exposure to the air.

In testimony whereof, we affiX our signatures.

MAXIMILIAN PAUL SCHMIDT.

OTTO LIMPACH. 

